Optimization of the reaction conditions (N.D. = not detected)^a.

Entry	Cat. [Pd]	Base	3ab (%)	4ab (%)	3a/4ac
1	Pd-1	NaOH	N.D.	N.D.	—
2	Pd-2	NaOH	<1	32	<1 : 32
3	Pd-3	NaOH	<1	31	<1 : 31
4	Pd-4	NaOH	65	6	11 : 1
5	Pd-5	NaOH	82	7	12 : 1
6	Pd-6	NaOH	95	3	32 : 1
7	Pd-6	LiOtBu	84	3	28 : 1
8	Pd-6	KOH	65	17	3.8 : 1
9	Pd-6	Cs2CO3	34	1	34 : 1
10d	Pd-6	Cs2CO3	91	3	30 : 1
11	Pd-6	K3PO4	N.D.	N.D.	—
12	Pd-6	K2CO3	N.D.	N.D.	—
13	Pd-6	—	N.D.	N.D.	—
14	—	NaOH	N.D.	N.D.	—
15e	Pd-6	NaOH	93	3	30 : 1

^aReaction conditions: 1a (0.1 mmol), 2a (0.2 mmol), Pd-PEPPSI catalyst (5.0 mol%), base (0.2 mmol), THF (1.0 mL), 100 °C, 1 h under N₂ unless otherwise noted.

^bNMR yields were based on 1a and determined by ¹H NMR using CH₂Br₂ as an internal standard.

^cThe 3a/4a ratio was determined by ¹H NMR analysis of the crude mixtures.

^d6 h.

^e1a (1.0 mmol), 2a (2.0 mmol), Pd-6 (2.5 mol%), NaOH (1.5 mmol), THF (6.0 mL).